12 letters · 16 points in Scrabble
adjective associated by chance and not an integral part; - Frederick W. Robertson
originFrom Medieval Latin adventītius (“coming from abroad, extraneous”), a corruption of Latin adventīcius (“foreign, strange, accidental”), from adventus (“arrival, coming, approach, advent”) + -īcius (suffix forming adjectives), from adveniō (“to arrive”) + -tus (suffix forming action nouns).
Etymology from Wiktionary, CC BY-SA 3.0